Microsoft wireless mouse with a mind of its own?

I recently installed a wireless mouse and keyboard from Microsoft to try and cut down the number of cables around my desk.

I have to say I am highly disappointed with the mouse as it tends to have a mind of its own... its scroll wheel only seems to work half the time and reading web pages is getting to be a frustrating task. Has anyone else got a Microsoft wireless mouse that doesn't work as well that one would hope for?

My problem is that I bought it months ago and its unlikely the store I bought it from will refund me.... I'll try for a replacement but if anyone knows of a better wireless mouse or keyboard combo then do let me know.